As communications technologies and communications services develop, location services are playing an important role as an indispensable part of mobile communications and personal communications services. An accurate and efficient positioning method is required for all location services based on a location of a mobile terminal, for example, intelligent traffic, vehicle navigation, traveling guidance, emergency alarming, and network planning and optimization. However, the currently widely used Global Positioning System (GPS) positioning technology cannot implement indoor positioning because no satellite signal is received indoors or a signal received indoors is excessively weak. Some indoor positioning technologies, for example, indoor positioning technologies based on a wireless local area network, Bluetooth, and the like, can implement indoor positioning, but require installation of massive third-party devices. This not only leads to high installation and maintenance costs, but also results in unstable system performance due to great environmental impact. At present, with popularization of smartphones, using a mobile telecommunications network to perform indoor positioning has become a popular positioning approach.
A frequently used positioning method based on a mobile telecommunications network is the observed time difference of arrival (OTDOA) technology. In a positioning process of this positioning method, after receiving different positioning reference signals (PRS) sent by a plurality of base stations, a terminal device calculates a time difference between each two received PRSs, to obtain a plurality of time differences, and sends, to a positioning server, the plurality of time differences and a base station identifier corresponding to each of the time differences. For each time difference and a base station identifier corresponding to the time difference, the positioning server calculates a hyperbolic positioning area based on the time difference and a base station location corresponding to the base station identifier, to finally obtain a plurality of hyperbolic positioning areas. Then, location information of the terminal device is obtained by calculating an intersection point of the plurality of hyperbolic positioning areas.
The described positioning method however is subject to at least the following problem:
In the positioning process, a node participating in positioning is a macro base station. For an indoor environment, due to impact of a propagation environment such as a multipath environment or a non line of sight (NLOS) environment, quality of a signal received by a terminal device is weak, or even no signal is received. As a result, accurate positioning cannot be implemented, and therefore positioning accuracy is poor.